This filter was found in an American publication from the 1980s. The circuit can be implemented with any operational amplifier. The power supply must be symmetrical.
Found in Linear Technology documentation from the 1980s, this generator uses integrated circuits...
This circuit shows how to use common logic functions to divide a frequency by 7. The output signal...
Found in Motorola documentation from the 90's, this circuit has a high input impedance. The power...